Technical Field:
The present disclosure relates to a fixed engine and rotating proprotor arrangement for a tiltrotor aircraft. The present disclosure also relates to a method and apparatus of connecting a fixed drive system to a rotating drive system for a tiltrotor aircraft.
Description of Related Art:
A conventional tiltrotor aircraft configuration can include a fixed engine with a rotating proprotor; however, conventional packaging arrangements of the fixed engine and the rotating proprotor can have significant shortcomings. Further, the location of the fixed engine and the rotating proprotor in relation to each other, as well as to the wing structure, can have significant influence upon the size and weight of the supporting structure, as well as the complexity of servicing procedures. For example, a rotating proprotor that is cantilevered outboard of the tip end of the wing can require significant structure to adequately support and prevent operationally induced deflection. Further, a rotating proprotor embedded in the wing structure can be difficult and time-consuming to perform maintenance thereon.
Hence, there is a need for a fixed engine and rotating proprotor arrangement that can be adequately supported with minimal structural mass, while also providing efficient maintainability.
Furthermore, a tiltrotor aircraft may have a fixed engine and a rotating proprotor with a gear and shaft to transfer torque therebetween. During operation, the fixed engine and the rotating proprotor may each endure a different operational loading which can induce operational misalignment therebetween. Also, misalignment can result from manufacturing and assembly tolerances. Designing the aircraft with structure with sufficient strength to resist the operational and tolerance misalignment therebetween can be undesirable due to the weight thereof. Further, conventional tiltrotor aircraft may have a torque transferring shaft between the fixed engine and the rotating proprotor that is burdensome to remove for maintenance and/or inspection, thus increasing the operational costs associated with operating the aircraft and performing maintenance and/or inspection thereof.
Hence, there is a need for a torque transferring device between a fixed engine system and a rotating proprotor of a tiltrotor aircraft that can allow for misalignment between the two. Further, there is a need for a torque transferring shaft that can be easily removed during a maintenance and/or inspection procedure.